Review looms for cancer vaccine

NEW YORK (CNNMoney.com) -- Provenge, an experimental prostate cancer treatment from the drug company Dendreon, could have a rough time winning over Food and Drug Administration advisors on Thursday, analysts say.

A panel of FDA experts is expected to vote on whether they consider Provenge good enough for the agency's approval. The result of this vote is taken as advice by the FDA at a later time, when it decides whether to approve the treatment. But some analysts are concerned about what they've read in FDA documents, which seem to demonstrate a negative sentiment towards the drug.

Provenge is an experimental vaccine that would be used as a treatment rather than a preventative like most other vaccines. FDA documents note that two late-stage studies of the vaccine failed to meet their goals in slowing the progression of prostate cancer. There has been some indication that the drug might increase survival time, but the FDA documents said it was hard to determine whether that was the result of chance or if the drug had demonstrable success against prostate cancer.

About one-fourth of investors holding Dendreon (up $0.53 to $5.15, Charts) stock have cast a black cloud over the company by selling the stock short.

"I don't think this vaccine gets approved ever," said Jonathan Aschoff, analyst for Brean, Murray, Carret & Co., who rates the company a "sell." Aschoff projects that the stock price will be "cut in half" following a negative vote from FDA analysts.

Aschoff said he is particularly concerned about the incidence of strokes in Provenge patients during late-stage trials. Another analyst, Maged Shenouda of UBS, referred to these strokes as "a potential safety signal" and therefore reason for concern.

"Given these comments [from the FDA documents,] as well as our view that Provenge lacks compelling efficacy evidence, we continue to believe that the FDA will require additional trial data before final approval," wrote Shenouda in a published note.

But Thomas Farrington, a prostate cancer survivor as well as president and founder of the Prostate Health Education Network, hopes that the FDA approves Provenge because of the data showing that it might prolong survival.

Farrington, who plans to speak on behalf of the vaccine at the FDA panel, also supports Provenge because it would be a new type of immunotherapy - a vaccine used as a cancer treatment - which might lead to other types of treatment.

"I certainly hope the FDA sees the wisdom of this drug as a potential break-through," said Farrington. "Immunotherapy might be the magic bullet for which we're hopeful."

Seattle-based Dendreon is a biotech, an area of drug development that is heavily involved in cancer treatments. Amgen (down $0.18 to $56.03, Charts) and Genentech (down $0.39 to $82.16, Charts), the two biggest biotechs in the world, are also focused on cancer treatments.

A Dendreon spokesman did not return a phone message this morning. Companies generally don't comment prior to FDA advisory votes.

The analysts quoted in this story do not own shares of company stocks mentioned here, though UBS and Brean, Murray, Carret & Co. make a market in Dendreon.